Posted on by Nancy Atkinson

13 Things That Saved Apollo 13, Part 8: The Command Module Wasn’t Severed

This view of the damaged Apollo 13 Service Module (SM) was photographed by a maurer 16mm motion picture camera from the Lunar Module/Command Module following SM jettisoning. Credit: NASA

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Note: To celebrate the 40th anniversary of the Apollo 13 mission, for 13 days, Universe Today will feature “13 Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.

When the Apollo 13 crew jettisoned the crippled Service Module as they approached Earth, they saw the extent of the damage from the explosion of an oxygen tank. “There’s one whole side of that spacecraft missing!” Jim Lovell radioed to Mission Control, his voice reflecting his incredulousness at seeing the damage of a 13-ft panel blown off the spacecraft. However, the situation could have been more dire. The heat shield on the Command Module could have been damaged. What’s more, NASA engineer Jerry Woodfill said that instead of the panel blowing out, the explosion could have — and maybe should have –severed the Command Module from the Service Module.

Graphic of the CSM. Credit: NASA

Photos taken by the Apollo 13 crew after the service module was jettisoned in preparation for the command module’s reentry via the heat shield revealed that not only was the panel missing from the side of the spacecraft — blown into the vastness of space by the exploding pressure of the detonating oxygen – there was also damage to the Hi Gain Antenna, at the right of the vehicle drawing above, indicating the panel had catapulted into space, striking the antenna. What the images couldn’t show, and what the Apollo 13 crew couldn’t see was if there was any damage to the Command Module’s heat shield.

“The structural design of the interior of the Service Module is that it has a long open tunnel-like volume in the center of the module, about 30 inches by 13 feet,” said Woodfill. “The tunnel is much like a chimney such that gases, liquids, or particles could readily move through it toward the main engine bell at the right and the heat shield at the left. The tunnel is not sealed so that the explosive force of the burning oxygen from the exploded O2 tank 2 could escape into and around the tunnel in the direction of both the heat shield and main engine.”

Woodfill said concern was voiced in Mission Control that shrapnel from the exploding tank had entered the tunnel, and perhaps ultimately caused damage to both the heat shield and main engine. The main engine wasn’t the biggest issue, as the crew was able to use the lunar lander’s descent engine. (see our previous article , “Using the LM for Propulsion.”) But there was only one heat shield, and it had to work to enable the capsule and the crew to survive the fiery reentry through Earth’s atmosphere.

Thankfully, as it turned out ,the heat shield wasn’t damaged.

The recovery of the Apollo 13 Command Module. Credit: NASA

But almost miraculously, Woodfill said, the command module and service module remained connected following the explosion, while the internal pressure of the explosion rocketed the exterior panel into space.

“The attachment strength of the Service Module panel to the structure required a considerable internal pressure of 24 pounds per square inch for severing it from the service module,” Woodfill said. “A much lower pressure was required to separate the Command Module with its heat shield from the Service Module, only 10 pound per square inch. One can only speculate on why the panel blew and the crew capsule/service module attachment remained intact.”

Since there is no air pressure in space, Woodfill explained, the force which held the vehicles together was the strength of their mechanical attachments.

“Two pressures were at work,” he said. “Each attempted to overcome respective attachment forces: the force which attached the Service Module to the Command capsule and the force which attached the Service Module panel to the Service Module. Because the explosive pressure force of the oxygen was immediately applied in great strength to the panel, this overwhelming force would be expected to blast that panel apart from the vehicle, exceeding the 24 pound per square inch attachment strength. However, venting of residual explosive oxygen into the framework of the Service Module could well be expected to overcome the attachment strength between the two vehicles, separating them.”

Yet, it did not. Why?

Sequence photo from 16mm motion picture film of test at Langley Research Center which seeks to determine mechanism by which Apollo 13 panel was separated from Service Module. Credit: NASA. Click image for more information

“Apparently, the presence of ‘tankage’ and other structure acted to mitigate and dissipate the sudden pressure spike before it reached the interface between the vehicles,” Woodfill said. “However, if a shard from the exploded O2 tank 2 had punctured any of the adjacent tanks, likely a secondary explosion of any of them would have propagated both the explosion and build up of pressure. In that event, certainly, the vehicles would have experienced either a fatal separation or fatal damage to the heat shield.

A piece of shrapnel did fracture the plumbing between the oxygen tanks that allowed the oxygen to leak out of Tank 1, causing the complete loss of power in the Command Module, for without oxygen the fuel cells couldn’t work.

Some may say that having the Service Module attached to the Command Module wasn’t important – it was just dead weight anyway. However, other problems could have developed without the Service Module attached, according the Apollo 13 Failure Report. Having the heat shield exposed to low temperatures for a long period could have damaged it, and internal Command Module thermal problems could arise if the Service Module was jettisoned too early.

Additionally, flight control problems were anticipated if the Command Module wasn’t attached.
The immediate loss of the Service Module would have meant immediate loss of the residual power from the fuel cells while the crew and mission control wrestled to understand the problem. This would have required a much greater power drain on those emergency batteries to the extent that one wonders if the later “trickle-charge” from the lander’s batteries would have been sufficient for reentry.

The crew of Apollo 13, Jim Lovell, Jack Swigert and Fred Haise, during a post-flight debrief. Credit: NASA

Of course, since the Service Module was jettisoned before the crew re-entered (and the SM itself later burned up in the Earth’s atmosphere) no one could do any “forensic analysis” or an engineering “autopsy” on that part of the spacecraft.

“To me, it is amazing that, one, the heat shield wasn’t damaged from the explosion, and two, the connection that could withstand higher pressure ended up blowing, while the weaker connection stayed together,” said Woodfill.

But those were among the many things that saved Apollo 13.

Next: Part 9: Which tank was damaged

Earlier articles from the “13 Things That Saved Apollo 13” series:

Introduction

Part 1: Timing

Part 2: The Hatch That Wouldn’t Close

Part 3: Charlie Duke’s Measles

Part 4: Using the LM for Propulsion

Part 5: Unexplained Shutdown of the Saturn V Center Engine

Part 6: Navigating by Earth’s Terminator

Part 7: The Apollo 1 Fire

Part 8: The Command Module Wasn’t Severed

Part 9: Position of the Tanks

Part 10: Duct Tape

Part 11: A Hollywood Movie

Part 12: Lunar Orbit Rendezvous

Part 13: The Mission Operations Team

Also:

Your Questions about Apollo 13 Answered by Jerry Woodfill (Part 1)

More Reader Questions about Apollo 13 Answered by Jerry Woodfill (part 2)

Final Round of Apollo 13 Questions Answered by Jerry Woodfill (part 3)

Never Before Published Images of Apollo 13’s Recovery

Listen to an interview of Jerry Woodfill on the 365 Days of Astronomy podcast.

Posted on by Nancy Atkinson

Shocking! Lunar Craters May Be Electrified

Graphic of how the solar wind flows over the Moon. Credit: NLSI

The Moon keeps getting more interesting all the time! But now comes “shocking” news that exploring polar craters could be much harder and more dangerous than originally thought. New research shows that as the solar wind flows over natural obstructions on the moon, such as the rims of craters at the poles, the craters could be charged to hundreds of volts. “In a nutshell, what we’re finding is that the polar craters are very unusual electrical environments, and in particular there can be large surface charging at the bottom of these craters,” said William Farrell from Goddard Space Flight Center, lead author of a new research on the Moon’s environment.

The moon’s orientation to the sun keeps the bottoms of polar craters in permanent shadow, allowing temperatures there to plunge below minus 400 degrees Fahrenheit, cold enough to store volatile material like water for billions of years. And of course, any resources that may lie in those craters are of interest for any future explorers, should astronauts ever return to the Moon.
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“However, our research suggests that, in addition to the wicked cold, explorers and robots at the bottoms of polar lunar craters may have to contend with a complex electrical environment as well, which can affect surface chemistry, static discharge, and dust cling,” said Farrell, who is part of a lunar Dream Team — the Lunar Science Institute’s Dynamic Response of the Environment at the moon (DREAM) project, which is also part of NASA’s Lunar Science Institute.

Solar wind inflow into craters can erode the surface, which affects recently discovered water molecules. Static discharge could short out sensitive equipment, while the sticky and extremely abrasive lunar dust could wear out spacesuits and may be hazardous if tracked inside spacecraft and inhaled over long periods.

The solar wind is a thin gas of electrically charged components of atoms – negatively charged electrons and positively charged ions — that is constantly blowing from the surface of the sun into space. Since the moon is only slightly tilted compared to the sun, the solar wind flows almost horizontally over the lunar surface at the poles and along the region where day transitions to night, called the terminator.

The researchers created computer simulations to discover what happens when the solar wind flows over the rims of polar craters. They discovered that in some ways, the solar wind behaves like wind on Earth — flowing into deep polar valleys and crater floors. Unlike wind on Earth, the dual electron-ion composition of the solar wind may create an unusual electric charge on the side of the mountain or crater wall; that is, on the inside of the rim directly below the solar wind flow.

Since electrons are over 1,000 times lighter than ions, the lighter electrons in the solar wind rush into a lunar crater or valley ahead of the heavy ions, creating a negatively charged region inside the crater. The ions eventually catch up, but rain into the crater at consistently lower concentrations than that of the electrons. This imbalance in the crater makes the inside walls and floor acquire a negative electric charge. The calculations reveal that the electron/ion separation effect is most extreme on a crater’s leeward edge – along the inside crater wall and at the crater floor nearest the solar wind flow. Along this inner edge, the heavy ions have the greatest difficulty getting to the surface. Compared to the electrons, they act like a tractor-trailer struggling to follow a motorcycle; they just can’t make as sharp a turn over the mountain top as the electrons.

“The electrons build up an electron cloud on this leeward edge of the crater wall and floor, which can create an unusually large negative charge of a few hundred Volts relative to the dense solar wind flowing over the top,” said Farrell.

The negative charge along this leeward edge won’t build up indefinitely. Eventually, the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow. The team believes one possible source for this current could be negatively charged dust that is repelled by the negatively charged surface, gets levitated and flows away from this highly charged region. “The Apollo astronauts in the orbiting Command Module saw faint rays on the lunar horizon during sunrise that might have been scattered light from electrically lofted dust,” said Farrell. “Additionally, the Apollo 17 mission landed at a site similar to a crater environment – the Taurus-Littrow valley. The Lunar Ejecta and Meteorite Experiment left by the Apollo 17 astronauts detected impacts from dust at terminator crossings where the solar wind is nearly-horizontal flowing, similar to the situation over polar craters.”

“This important work by Dr. Farrell and his team is further evidence that our view on the moon has changed dramatically in recent years,” said Gregory Schmidt, deputy director of the NASA Lunar Science Institute at NASA’s Ames Research Center, Moffett Field, Calif. “It has a dynamic and fascinating environment that we are only beginning to understand.”

Next steps for the team include more complex computer models. “We want to develop a fully three-dimensional model to examine the effects of solar wind expansion around the edges of a mountain. We now examine the vertical expansion, but we want to also know what happens horizontally,” said Farrell. As early as 2012, NASA will launch the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission that will orbit the moon and could look for the dust flows predicted by the team’s research.

The research was published March 24 in the Journal of Geophysical Research.

Source: NLSI

Posted on by Nancy Atkinson

Astronomy Cast Ep. 180: Albedo

Enceladus, the highest albedo in the Solar System. Image credit: NASA/SSI

Why are some objects in the Solar System bright while others are dim? Much of an object’s brightness is caused by its albedo, or how well it reflects radiation from the Sun. If you want to know how big a distant moon, comet, or asteroid is, you’ve got to know its albedo.

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Nancy Atkinson

Carnival of Space #150

This week’s Carnival of Space, the big 1-5-0, is hosted by Brian Wang over at Next Big Future.

Click here to read the Carnival of Space #150

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

Posted on by Jean Tate

Hubble’s 20th: At Least as Good as Any Human Photographer

NGC 3314 (click for larger version)

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Note: To celebrate the 20th anniversary of the Hubble Space Telescope, for ten days, Universe Today will feature highlights from two year slices of the life of the Hubble, focusing on its achievements as an astronomical observatory. Today’s article looks at the period April 2000 to April 2002.

The International Center for Photography gave its 2000 Infinity Award to the Hubble Heritage Project, in the Applied Photography section. And what did that team choose to showcase their award? The above image of NGC 3314! Clearly the Hubble has had a deep impact far beyond the astronomical community and space fans.

Columbia’s last flight, before the one that ended in disaster, was STS-109, or the Hubble servicing mission 3B, in March, 2002. In terms of imaging capability, it was the most dramatic; the Advanced Camera for Surveys (ACS) was installed (replacing the Faint Object Camera), and NICMOS’ cooling system was replaced (giving the Hubble ‘night vision’ again – it could see in the infrared once more). I’ll be covering the cornucopia of science results from ACS in later articles.

My pick for the Hubble image most of you, my readers, would put at the top your ‘what I remember from these two years’ is Stephan’s Quintet.

Stephan's Quintet (Credit: ESA)


Hubble Space Telescope Faint Object Spectrograph (Credit: NASA)

What we see on a webpage or in a magazine, when we look at a Hubble image, resembles a photograph. What an astronomer sees is data, glorious data, in all its numerical detail (astronomers even invented a special file format for their data, called FITS, short for flexible image transport system; more about it here). And among the most critical aspect of astronomical data is its calibration, e.g. the function which relates pixel values to things like flux (which may be measured in janskys, or ergs per second per square meter per hertz). But how do you calibrate an instrument that’s aboard the Hubble? You turn to the Instrument Physical Modelling Group, part of the Space Telescope European Coordinating Facility! This highly specialist team actually models the Hubble’s instruments, in software, from first (physics) principles, and from those models produces robust software for taking the raw data from a Hubble instrument and producing calibrated, science-grade data. They then make their results public, for anyone and everyone to use; for example the Faint Object Spectrograph Post-Operational Archive (you can read the details of their work in ST-ECF Newsletter 29).

Another behind-the-scenes activity is the production of the Hubble Guide Star Catalog, essential for the Hubble’s smooth operation (and a major boon to amateurs); 2001 saw a major new release (II).
A MACHO (Credit: European Space Agency, European Southern Observatory and the MACHO project team)

Every now and then a (faint) star will pass close to the line of sight of a more (bright) distant star, and we will see the (distant) star brighten in a characteristic way (due to gravitational lensing). One kind of such lensing is the object of many astronomers’ desire, a MACHO (massive compact halo object); even more desirable is to see both the lensed and lensing stars, as separate points of light, some time after the event. Hubble observed just such a rarity.
Comet LINEAR (Credit: NASA and Hal Weaver (The Johns Hopkins University, Baltimore, MD))

Comets are fragile things; their very tails tell tales of constant erosion at the hands of sunlight. And when they die, do they do so with a bang, or merely a whimper? Hubble captured an example of the latter (Comet LINEAR is no more).
Horsehead Nebula (Credit: NASA, NOAO, ESA and The Hubble Heritage Team (STScI/AURA))

But the Hubble isn’t only for astronomers, even amateur astronomers; it’s there for us all, to take pictures that awe and inspire us. And by popular demand, the famous Horsehead nebula, as never seen by anyone using a telescope down here on Earth.

It was during these two years that Universe Today began its coverage of the Hubble (and other astronomy and space topics); for example Hubble Reveals Backward Galaxy (however, I can’t find any Universe Today stories from this period with Hubble images; can you help me out please, dear reader?)

Tomorrow: 2002 and 2003.

Previous articles:
Hubble’s 10th Birthday Gift: Measurement of the Hubble Constant
Hubble at 8: So Many Discoveries, So Quickly
Hubble’s 20 Years: Now We Are Six
Hubble’s 20 Years: Time for 20/20 Vision
Hubble: It Was Twenty Years Ago Today

Sources: HubbleSite, European Homepage for the NASA/ESA Hubble Space Telescope, The SAO/NASA Astrophysics Data System

Posted on by Nancy Atkinson

STS-131, the Mission in Pictures

Amazing image from Soichi Noguchi of the shuttle. "Midnight running! Galaxy Express 131, Discovery," he Tweeted. Credit: Soichi Noguchi

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Space shuttle Discovery’s landing was delayed a day because of uncooperative weather at Kennedy Space Center and the crew of STS-131 will try again on Tuesday to land. But in the meantime the delay provides a great opportunity to look back at the very successful mission with a set of amazing pictures from space. This beautiful image, top, shows the station’s robotic Canadarm2 grappling the Leonardo Multi-purpose Logistics Module (MPLM) from the payload bay of the docked Discovery for relocation to a port on the Harmony node of the International Space Station. The bright sun and Earth’s horizon provide the backdrop for the scene, while the Canadian-built Dextre robot looks on. Enjoy a gallery of images, below.

Clay Anderson during an EVA. Credit: NASA

Clay works outside the ISS during STS-131’s first EVA. During the six-hour, 27-minute spacewalk, Anderson and Rick Mastracchio (visible in the reflection of Anderson’s helmet visor), mission specialist, helped move a new 1,700-pound ammonia tank from space shuttle Discovery’s cargo bay to a temporary parking place on the station, retrieved an experiment from the Japanese Kibo Laboratory exposed facility and replaced a Rate Gyro Assembly on one of the truss segments.

Discovery during the rendezvous and docking with the ISS on April 7, 2010. Credit: NASA

Discovery and the International Space Station are in the midst of their rendezvous and docking activities in this image photographed by an Expedition 23 crew member aboard the ISS. Part of a docked Russian spacecraft can be seen in the foreground.

Rick Mastracchio during the first EVA of the mission. Credit: NASA
Amazing image from Soichi Noguchi of the shuttle. He tweeted: Midnight running! Galaxy Express 131, Discovery. Credit: Soichi Noguchi

Astronaut Soichi Noguchi has taken some of the most incredible images while on the ISS. Here’s one more awesome shot of Discovery while docked to the ISS during the STS-131 mission.

Naoko Yamazaki is pictured in a window of the Cupola. Credit: NASA
Commander Alan Poindexter and Pilot Jim Dutton in Discovery's cockpit. Credit: NASA

Compare this image, above, of Commander Alan Poindexter and Pilot Jim Dutton in the “real” shuttle cockpit, to below, the shuttle simulator.

Commander Alan Poindexter and pilot Jim Dutton in shuttle simulator. Credit: NASA
Japan Aerospace Exploration Agency (JAXA) astronauts Soichi Noguchi, Expedition 23 flight engineer; and Naoko Yamazaki (right), STS-131 mission specialist; along NASA astronaut Stephanie Wilson in the Destiny Lab. Credit: NASA.

This mission brought together two Japanese astronauts Soichi Noguchi, Expedition 23 flight engineer; and Naoko Yamazaki (right), STS-131 mission specialist; along NASA astronaut Stephanie Wilson,

A unique view of the ISS. Credit: NASA

A unique view of a part of the ISS, backdropped by the blackness of space and Earth’s horizon. Visible are the Japanese Kibo complex of and a set of solar arrays. This image was photographed by an STS-131 crew member while space shuttle Discovery was docked with the station.

Clay Anderson with a ball of water. Credit: NASA

The microgravity environment of space provides a great place to play — experimenting with a water is always fun and it likely happens every mission!

Four women in space at once for the first time. Credit: NASA

For the first time, four women were in space together during the STS-131 mission, with three from the shuttle crew and one from the ISS. Pictured clockwise (from the lower right) are NASA astronauts Dorothy Metcalf-Lindenburger, Stephanie Wilson, both STS-131 mission specialists; and Tracy Caldwell Dyson, Expedition 23 flight engineer; along with Japan Aerospace Exploration Agency (JAXA) astronaut Naoko Yamazaki, STS-131 mission specialist.

The STS-131 crew in the ISS's Cupola. Credit: NASA

Love this image of the STS-131 crew in the Cupola. Pictured counter-clockwise (from top left) are NASA astronauts Alan Poindexter, commander; James P. Dutton Jr., pilot; Dorothy Metcalf-Lindenburger, Rick Mastracchio, Japan Aerospace Exploration Agency (JAXA) astronaut Naoko Yamazaki, NASA astronauts Clayton Anderson and Stephanie Wilson.

Time-lapse image of the launch of STS-131. Credit: NASA

Back to where the mission started, with a great time-lapse image of Discovery’s launch for STS-131. For more great launch images, see our launch gallery from Universe Today photographer Alan Walters and writer Ken Kremer, who were both at the launch.

Posted on by Jean Tate

Universe Puzzle No. 10

Last week’s Universe Puzzle was fun to do wasn’t it?

Well, this week’s is number ten (how time flies), which is a good time to get some feedback.

Do you enjoy these puzzles? What do you particularly like? Dislike? Would like to see changed? Would like to see more of? Let me know please! Either in the comments below, or drop me an email.

Once again, this week’s puzzle requires you to cudgel your brains a bit and do some lateral thinking (five minutes spent googling likely won’t be enough). But, as with all Universe Puzzles, this is a puzzle on a “Universal” topic – astronomy and astronomers; space, satellites, missions, and astronauts; planets, moons, telescopes, and so on.

What is brightest pre-telescopic nova?

As in: a nova before telescopes were used to observe the heavens.

UPDATE: Answer has been posted below.

This puzzle was designed to really cudgel your brains!

As several of you noted, the term ‘nova’ has had different meanings through the ages; specifically, it wasn’t until the 20th century that ‘novae’ were distinguished from ‘supernovae’. So in trying to solve the puzzle, do you look for historical ‘novae’ but not ‘supernovae’? Or both?

Then there’s the fact that what might have been called a ‘nova’ in the writings of someone in Europe (writing in a language close to, or derived from, Latin) may have been called something quite different by someone writing in China, or in Arabic … even though they were describing the exact same ‘new star’ in the sky. But then not every ‘guest star’ (a translation of a Chinese term) was a nova.

There’s more: I didn’t say it had to be nova that was recorded; there has been some success these last few years in finding light echos of ancient supernovae and extrapolating back. Perhaps someone has done this and someone determined that there would have been a particularly bright nova in 1234 (say), but because it was near the south celestial pole, it was highly unlikely to have been recorded by anyone (in a form that we could understand today) – no, this is highly unlikely, but you get the point.

Getting a little more imaginative: some GRBs are visible to the unaided eye. However, as they are visible for just a few seconds, tops, they’d likely not be recorded.

And so on.

Now the answer that I had in mind, taking all the above (and more; SGRs, Cataclysmic Variables, Dwarf Novae, Recurrent Novae, …) in account was SN1006, which is the historical (super)nova that is both reliable and has the highest estimated peak brightness.

Hon. Salacious B. Crumb , congratulations! You get an extra prize for looking into the known SNR (supernova remnants) to see if any had an estimated peak brightness greater than that of SN1006.

And of course “there’s no way to know” is, perhaps, the best answer of all!

Check back next week for another Universe Puzzle!

Posted on by Nancy Atkinson

Shuttle Will Fly Over Heart of US for Monday Morning Landing Attempt

STS-131 flight path for landing attempt. Credit: NASA.

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If the weather cooperates, space shuttle Discovery will attempt to land in Florida Monday morning using a so-called “descending node” where the trajectory will take it across the heart of the continental US. “The neat thing about the descending opportunities is it’s going to come across the country and folks will get a good opportunity, hopefully, to see the orbiter as it goes overhead,” said NASA entry flight director Bryan Lunney. This flight trajectoray hasn’t been used since before the Columbia disaster in 2003, to avoid flying over densely populated areas of the US. This descending node trajectory is favorable for adding extra crew time to the mission. The plan is for Discovery’s braking rockets to fire for three minutes and 11 seconds starting at 7:43:20 a.m. EDT Monday. This will slow the shuttle by about 217 mph for a landing at the Shuttle Landing Facility at Kennedy Space Center at 8:48:36 a.m. The second opportunity would be at 10:23:30 a.m.

But rain is in the forecast for Florida in Monday morning, so time will tell if the view will be available. As the shuttle crosses the Canadian border it would be only 43 miles high, providing a good view for viewers below.

According to Bill Harwood at CBS news, here is the flight path and expected speeds over each location, as marked on the map, above.

1. South of the Queen Charlotte Islands (western Canada)
2. Over British Columbia, northeast of Vancouver
3. Over southern Alberta province
4. Over Montana, flying over Fort Peck Lake (Mach 22)
5. Across the western border of North Dakota, then over northern South Dakota tracking northwest to southeast, directly over the capital of Pierre
6. Across Iowa directly over Sioux City and southwest of Des Moines and Council Bluffs, Iowa (Mach 18)
7. Over the heart of Missouri, between Kansas City and St. Louis (Mach 16)
8. Over the eastern border of Arkansas and Tennessee, east of Memphis (Mach 14)
9. Over NE Mississippi, northeast of Tupelo (Mach 12)
10. Over Alabama tracking northwest to southeast from Birmingham to Columbus, Georgia (Mach 10)
11. Over southwest Georgia south of Americus
12. Over Florida, almost directly over Jacksonville (Mach 4)
13. West of St. Augustine and Daytona Beach, onto KSC

Source: CBS, NASA

Posted on by Nancy Atkinson

Incredible Images of Iceland Volcano from Just a Few Kilometers Away

Lightning visible in the plume of the Eyjafjallajokull volcano in Iceland on April 17, 2010. Image courtesy of Snaevarr Gudmundsson.

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Astronomer Snaevarr Gudmundsson from Iceland was able to travel to within just a few kilometers from the Eyjafjallajokull volcano, and shared his incredible close-up images with Universe Today. “I stayed near the volcano from about 16:00 hours to 22:00 hours on Saturday and watched its impressive eruption,” Gudmundsson said in an email to me. “Amazing event, awesome explosions of 1200 °C hot magma reaching ice and water. I shot more than 550 images during these hours of continuous enjoyment. Sounds ridiculous but its ever changing appearance was never boring.”

The massive plume put on an impressive display – from lightning forming within the plume to an incredible amount of spewing ash. On one of following pictures you can see helicopter for size comparison of the plume

The massive plume of Eyjafjallajokull volcano dwarfs a helicopter flying nearby (upper left). Image courtesy of and copyright Snaevarr Gudmundsson.

Gudmundsson said he and other photographers were a safe distance from the eruption, but were a few kilometers away. “Nearby was a small river and its prominent sound prevented us from hearing much in the eruption itself except a loud roar from thunders from time to time,” he said. “During daylight we even glimpsed some lightning but at dusk (the photo is taken at about 22:00 in the evening) they were easily spotted especially during active periods of explosions.”

The plume of Eyjafjallajokull volcano on April 17, 2010. Image courtesy of and copyright Snaevarr Gudmundsson.

I asked if there was any smell associated with the Iceland volcano and Gudmundsson said there was a bit of sulphuric smell in the air even though they were in a location where the wind was blowing towards the volcano. “The ash went to the other side of the volcano, as you can suggest, making life miserable for farmers and households below, but the rest of it climbed to higher altitude and from there to Europe.”

“From the foot of the volcano to the prominent top, seen in front of the tephra cloud (seen on some of the photos) the overall height is about 1300 -1400 m,” Gudmundsson said. “When the eruption began a huge flood went down beneath the obvious glacier to the left from the crater. And if you look closely on the photo showing the foot hills under the mountain a lot of icebergs can be seen on the flood plain. Under that same glacier was a rather deep lagoon (can’t been seen but sat between the two high moraines on either side of it, in front of the glacier) but sediment from the eruption filled it up in only two days at most! That is unbelievable. I have climbed this glacier many times but to approach it one usually must traverse the moraine, around the lagoon to reach the ice. But suddenly it is gone.”

Another view of Eyjafjallajokull volcano on April 17, 2010. Image courtesy of and copyright Snaevarr Gudmundsson.

Gudmundsson said the flood paths can be seen below the glacier as a narrow gorges carved into rather soft volcanic sediment.

Some of the latest reports from Iceland say that in some areas the volcanic fallout has been significant, clogging car engines, turning grass grey and reducing visibility to just a few meters.

The police say driving conditions can be very difficult in these places, but the area affected is remote with only a few hundred people, most of them living in isolated homes and many of them farmers. They have been advised to stay inside with the windows and doors shut and if they do venture out to wear goggles and a mask.

The staff of Landhelgisgæslan (Icelandic Coastal Patrol) captured this radar image of the craters in Eyjafjallajökull on Friday. There are three main openings and each one is 200-500m in diameter.

Radar image of the volcano, taken by the Icelandic Coastal Patrol.

Our very special thanks to Snaevarr Gudmundsson for sharing his images and experiences of seeing the volcano “up close and personal.” Also thanks to Col Maybury of radio station 2NUR in Newcastle, Australia for connecting me with Snaevarr (yes my connection to Iceland came through Australia!) and also thanks to erlinger on Twitter for help with Icelandic translations of news reports.

Other sources: mbl.is, BBC

Here are some more Iceland pictures.

Posted on by Jean Tate

Hubble’s 10th Birthday Gift: Measurement of the Hubble Constant

HDF-S (Credit: R. Williams (STScI), the HDF-S Team, and NASA). Click for a larger version

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Note: To celebrate the 20th anniversary of the Hubble Space Telescope, for ten days, Universe Today will feature highlights from two year slices of the life of the Hubble, focusing on its achievements as an astronomical observatory. Today’s article looks at the period April 1998 to April 2000.

In October 1998, Hubble complemented the original Hubble Deep Field with Hubble Deep Field South (HDF-S). Three instruments – NICMOS, STIS, and WFPC2 – stared at a tiny spot in the sky for ten days (more images here).

Hubble got dizzy in November 1999; the fourth (of six) gyroscopes failed, and the observatory was put into safe mode. The third servicing mission, planned for mid-2000, was split in two, with 3A being done in December 1999. Along with replacing all the gyros, Hubble got a computer upgrade … to a 486 model (did you ever own a PC with a 486 CPU?)

I reckon the image which most of us remember best from these two years is this one of M57, yet another planetary nebula.

M57 (Credit: The Hubble Heritage Team (AURA/STScI/NASA))


Wendy Freedman (CARLA BEFERA PUBLIC RELATIONS)

“Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant” is one of the most heavily cited papers in astronomy, perhaps even science, period. It also happens to be one of easiest to read, and is likely to serve as a model for a long time. It is based on a great deal of ‘Hubble time’ (dedicated observations), but should anyone want use all the data from all that time, they are free to do so. Wendy Freedman is the lead author on that paper, and led this Hubble Key Project (HKP) from start to finish.
NGC 4603 with Cepheids marked (Credit: Jeffrey Newman (Univ. of California at Berkeley) and NASA)

At its heart, this HKP is a repeat of Edwin Hubble’s work, some seven decades earlier – observing lots of Cepheid variables in some 19 nearby galaxies, with the Hubble, and using the period-luminosity relationship to estimate the distances to them (Of course, there’s a very great deal more to it than that!). No prizes for guessing who the Hubble is named after, and why.
Copernicus, by Hubble (Credit: John Caldwell (York University, Ontario), Alex Storrs (STScI), and NASA)

The end of the Key Projects freed up more time for the Hubble to observe other things; some of which may surprise you. For example, many people think the Hubble cannot look at the Moon, much less take pictures of it.

To make some of Hubble’s best eye-candy more accessible, the Hubble Heritage Project was set up, in 1998. And what more appropriate eye candy is there, in a story about the Hubble, than Hubble’s variable nebula?
NGC 4650A (Credit: The Hubble Heritage Team (AURA/STScI/NASA))

And one of the things the Hubble Heritage team did was run a competition for the best image; the polar ring galaxy NGC 4650A won (was that your choice?); if you think this looks odd, it is … I rotated it 90 degrees (there’s no up or down in space).
HDF-S by NICMOS (Credit: R. Williams (STScI), the HDF-S Team, and NASA)

To close, two much less often seen HDF-S results, from NICMOS (above) and STIS (below).
HDF-S by STIS (Credit: R. Williams (STScI), the HDF-S Team, and NASA)

Tomorrow: 2000 and 2001.

Previous articles:
Hubble at 8: So Many Discoveries, So Quickly
Hubble’s 20 Years: Now We Are Six
Hubble’s 20 Years: Time for 20/20 Vision
Hubble: It Was Twenty Years Ago Today

Sources: HubbleSite, European Homepage for the NASA/ESA Hubble Space Telescope, The SAO/NASA Astrophysics Data System, Hubble Deep Field South